1. Field of the Invention
This invention relates generally to a method and apparatus for dissolving a treating material. More particularly, this invention relates to a method and apparatus for dissolving a solid soluble treating material to provide a solution of such material for feeding into a system to be treated.
2. Description of the Prior Art
Chlorine is used in many industrial applications for treating purposes. It can be used for sanitizing, bleaching, oxidizing and preventing the buildup of unwanted vegetable and animal matter such as algae and marine life. Although in some instances, the chlorine is supplied as gaseous chlorine or liquid sodium hypochlorite, a dry, solid calcium source of chlorine such as calcium hypochlorite offers many advantages over gaseous chlorine or liquid sodium hypochlorite. It is stable, concentrated and relatively easily handled. However, many industrial treating systems utilize a water based solution for treating purposes. In the presence of water, solid calcium hypochlorite tends to cake and become corrosive.
The solid chlorine-containing material may be metered directly into the system to be treated or dissolved and then metered into the system to be treated to provide the proper concentration of chlorine for the system to be treated. However, delivery systems for solids of this type tend to be expensive and, due to the caking and corrosion, tend to be unreliable.
A feeder for dissolving and feeding a solid soluble sanitizing material such as calcium hypochlorite, into a body of water such as a swimming pool is shown and described in U.S. Pat. No. 4,867,196, issued Sep. 19, 1989 to C. N. Zetena et al, and U.S. Pat. No. 5,133,381, issued Jul. 28, 1992 to Wood et al. The disclosure of both of these patents are hereby incorporated herein by reference in their entirety. As described in these patents, the feeder includes three separate chambers: a discharge chamber, a dissolving chamber and a removable solid tablet container or hopper. Water is fed into the dissolving chamber which contains tablets of calcium hypochlorite until the water rises to a point that a siphon tube, connected between the dissolving chamber and the discharge chamber, permits the solution in the dissolving chamber to flow into the discharge chamber.
While such feeders have been successful, their application has generally been limited to low volume applications such as swimming pools where the required concentration of available chlorine in the treating solution is relatively low, on the order of less than 2 percent. In many industrial applications, the required concentration of chlorine in the treating solution is at least 2 percent, and on the order of 5 percent or greater, and the required feed rate of available chlorine in a given time period is greater than that capable of being produced by such feeders.